The present invention relates to a system for assisting dentists and dental technicians in the forming and shaping of artificial frontal teeth so as to improve the appearance of a person""s smile.
In recent years, more attention is being paid to improving the aesthetic aspects of a patient""s teeth at the same time that the functional aspects are being improved. Particular attention is being directed to the anterior maxillary teeth inasmuch as they are most visible when a person smiles. It is desirable that the left and right central incisors be approximately bisected by the person""s mid-sagittal plane. In addition, it has been recognized that there is a desirable ratio between the width of the adjacent teeth, and that this ratio surprisingly is about the same for adjacent teeth. That is, it is considered desirable that the ratio of the width of the central incisor to the adjacent lateral incisor is the same as the ratio between the width of the lateral incisor to that of the adjacent canine tooth.
This proportion or ratio is believed to be common for many relationships of the human body and it also applies to the beauty of other objects. This is referred to in literature as the xe2x80x9cgolden numberxe2x80x9d or xe2x80x9cgolden proportionxe2x80x9d or xe2x80x9cgolden ratio.xe2x80x9d This ratio is 1:1.618 or 0.618:1. For example, if the width of the central incisor is the unit 1.618, the width of the adjacent lateral incisor should be 1, and the similar ratio should apply between the lateral incisor and the adjacent canine.
In the making of a cap for a tooth, such as a lateral incisor, at least the visible portions of the tooth are removed and replaced by material shaped to provide the desired appearance. This is typically accomplished by applying wax to the tooth stump, and shaping the wax to create the desired shape of the tooth. The wax model is then used to create a mold in which the cap is to be formed. It is desired that a tool or guide be provided which will assist the dentist or technician in the waxing operation.
Briefly stated, a waxing tool or guide is provided for forming artificial teeth. The guide is preferably in the form of a thin flat element to be mounted on a support, which is preferably in the form of a platform mounted to the lower frame of a dental articulator. The element forming the guide is provided with markings on its upper surface that indicate a desired relationship for a person""s anterior maxillary teeth. Preferably, this desired relationship between adjacent teeth is the above-mentioned golden proportion or ratio. Since the width of a central maxillary incisor varies, a set of guides can be provided, for example, with width changes in half mm changes, varying from 7 to 10 mm.
In use, a maxillary dental cast of the patient""s maxillary teeth is mounted on a frame such as the upper frame of a dental articulator with the cast being mounted in a known relationship with respect to a platform supporting the waxing guide in a relationship that simulates the patient""s maxillary teeth. This can perhaps be accomplished with more than one technique, but in a preferred approach, a face bow analyzer is provided having a bite fork adapted to be positioned within a patient""s mouth between the upper and lower teeth. An upper index tray is mounted on the upper surface of the bite fork and a lower index tray is secured to the lower surface of the bite fork. A line on the upper surface of the upper index tray is aligned with the incisal edges of the central incisors on a dental cast. This so-called incisal line is utilized as a reference for mounting a dental cast in the articulator. Dental impression material is applied to the index trays, and the assembly is positioned in the patient""s mouth and lightly gripped by the patient""s teeth while the dentist grips portions of the face bow extending out of the patient""s mouth. The patient""s incisors are aligned with the incisal line on the upper surface of the upper index tray. The face bow is then adjusted to a horizontal position and properly aligned with the patient""s sagittal plane. The face bow is then held in that position while the impression material hardens.
After that, the upper index tray is mounted on the above-mentioned platform which in turn is mounted on the lower frame of a dental articulator. The incisal line on the tray is aligned with a corresponding incisal line on the platform. The incisal line on the platform is either at a known distance or an average distance from the hinge axis of the dental articulator which corresponds to the distance between the incisal line and the hinge axis of the patient. The dental cast is then positioned in the upper index tray and secured to the upper frame of a dental articulator in a known manner. The dental cast is then in position to have the dental caps or other prosthetic element formed in wax. The upper index tray is removed from the mounting platform and is replaced by the waxing guide. The waxing guide is positioned so that a central line on the guide is aligned with the sagittal plane or dental midline of the dental cast and an incisal line on the guide is aligned with the appropriate incisal line on the mounting platform. With the dental cast positioned close to the waxing guide, the dentist or technician is then in position to form the desired artificial tooth or cap utilizing the guide as an alignment element so as to form the artificial tooth or cap with the desired proportion in relation to the adjacent teeth.